EMRFD Message Archive 9279

Message Date From Subject
9279 2013-10-21 18:17:07 patt896 Super J-Pole @ 126 MHz

I built one based upon N1HX's design:

Why did I not know that:

CPVC pipe is a conductor
Kevlar & carbon fiber tubes are conductors
Copper pipe comes in different sizes, K, L & M with different thicknesses and weights
1/2 inch copper is .625 OD
Copper is too heavy for a three element Super J-Pole
6061 Aluminum tube is available in 1/2 in OD and .625 OD
PVC CTS connectors are too weak to support a Super J-pole
Max Gain Systems offers fiberglass mast tubes which are non conductive, inter-sleeve, tubes in common OD & ID sizes
3/8 OD copper tube fits into 1/2 inch aluminum tubing if aluminum tube is drilled out with a 10mm or 13/32 inch bit
Shrink tubing can be used to mitigate small differences in ID tube sizes

I ended up with a Super J-pole that starts with 1/2 inch copper. Joined with 1/2 inch ID fiberglass, 1/2 inch OD aluminum
tube, 3/8 ID copper tube, 1/8 inch aluminum rod.

Works well.

But SWR is 1.0 @ 131 Mhz.